Том 88, № 7 (2018)

Experimentaly and theoretically, using the method of density functional theory, the structure of 2,2'-diphenyl-1-picrylhydrazyl radical and the mechanism of its reaction with di- and trihydroxybenzenes in non-ionizing media have been investigated. It was established that in nonpolar solvents the elimination of hydrogen atom from hydroxybenzene by the radical occurs as a conjugate transfer of proton and electron, as confirmed by the existence of a deuterium isotope effect as well as characteristic geometrical and electronic parameters of pre-reaction complexes and transition states of the reaction.

According to IR and ¹⁵N NMR spectroscopy data, bis(3-aminophenyl)phosphinic acid exists in the molecular form in the DMSO and DMF solutions. The molecular and ionic forms are in equilibrium in the solutions of triethylammonium salt of bis(3-aminophenyl)phosphinic acid in DMSO and DMF.

The reaction of 1-amino-2-nitroguanidine with α-diketones (butane-2,3-dione and 1,2-diphenylethanedione) produced new specimens of nitroamino-containing 1,2,4-triazines. The structure of the synthesized compounds of linear and heterocyclic series was confirmed by ¹H, ¹³C{¹H} NMR, IR, and UV spectra.

New 4-substituted 4H-1,2,4-triazole-3-thiol derivatives were synthesized by introducing benzylsulfanylethyl groups in the 5-position of the heterocycle. Alkylation of the thiol group provides additional pharmacophore thioether, carboxamide, carboxyl, and hydroxyethyl fragments. Regardless of the nature of the substituents in the position 5 aminomethylation and cyanoethylation proceed at the N₂ atom. The synthesized compounds were studied for anti-tumor activity and the effect on the methylation level of tumor DNA.

By arylation of 2-methyl-3-acetylfuran via the Gomberg–Bachmann reaction 5-(4-ethoxycarbonylphenyl)-, 5-(2-nitrophenyl), and 5-(4-nitrophenyl)-2-methyl-3-acetylfurans were synthesized. Carboethoxyhydrazones of 2-methyl-5-phenyl-3-acetylfuran and its phenyl-substituted analogs when treated with thionyl chloride form 4-(5-aryl-2-methylfuran-3-yl)-1,2,3-thiadiazoles by the Hurd–Mori reaction. Thermal stability of obtained compounds increases with the increase in electron-acceptor action of substituent in phenyl ring. Opening of thidiazole ring in the compounds synthesized under the action of potassium tert-butylate in THF in the presence of alkyl iodides leads to the corresponding alkylthioethynylfurans. Performing the reaction with potassium carbonate in DMF in the presence of excess morpholine permits the preparation of (2-methyl-5- arylfuran-3-yl)thioacetylmorpholides.

New metal–heterocycle S,S-complexes based on Cu(I) binary halides and a polydentate ligand, 1,2- bis(3,5-dimethyloxazol-4-ylmethylsulfanyl)ethane have been prepared. The obtained complexes have demonstrated high catalytic activity in aminomethylation of phenylacetylene with N,N,N',N'-tetramethylmethanediamine, bis(oxazolidin-3-yl)methane, or benzaldehyde–piperidine system.

The reaction of ZrCl₄ with 2,2-dimethylbutanoic acid in excess of the acid and also in o-xylene at boiling point of the solvent was studied. Formed zirconium tetrakis(2,2-dimethylbutanoate) is volatile in vacuum that allows its using as a precursor for the preparation of inorganic materials by chemical vapor deposition. During the reaction Zr(C₆H₁₁O₂)₄ is condensed to form polynuclear complexes.

A new Schiff base was prepared by the reaction of 4-methyl-7-hydroxy-8-formylcoumarin with N-aminomercaptotriazole. In solution and in solid phase the compound was shown to exist in the thione form. The compound reacts with Cu(II), Ni(II), Zn(II) and Cd(II) ions depending on the metal salt to give complexes of composition ML₂ or MHLX, where HL is monodeprotonated form of the ligand. Cu(II) and Ni(II) complexes were studied by spectral and magnetochemical methods. The Zn(II) and Cd(II) complexes exhibit fluorescence.

Complexes [Ph₃PCH₂C(O)Me][PtCl₃(DMSO-S)] and [Ph₃PCH₂CH=CH₂][PtCl₃(DMSO-S)] were synthesized by the reaction of organyltriphenylphosphonium chloride with potassium tetrachloroplatinate (2 : 1) in dimethyl sulfoxide. The reaction of but-2-enylbis(triphenylphosphonim) dichloride with potassium hexachloroplatinate or hexachloroplatinic acid leads to the formation of the complex [Ph₃PCH₂CH=CHCH₂PPh₃][PtCl₅(DMSO-S)]₂. Phosphorus atoms in the cations of the synthesized complexes have a tetrahedral surrounding, and the anions [PtCl₅(DMSO-S)]⁻ are square in shape.

The binding of gold(III) from solution in a 2 M HCl with thallium(I) dibutyl dithiocarbamate leads to the formation of ion-polymeric complex ([Au{S₂CN(C₄H₉)₂}₂][TlCl₄])_n, which was studied by (¹³С, ¹⁵N) MAS NMR spectroscopy and X-ray diffraction analysis. In the complex comprising the nonequivalent cations [Au{S₂CN(C₄H₉)₂}₂]⁺ (A and B) and anions [TlCl₄]^–, the supramolecular self-assembly is provided by secondary bonds Au···S and S···Cl. The former are involved in the formation of isomeric binuclear cations [А···А] and [В···В] that build the (···[А···А]···[В···В]···)_n polymeric chain; the latter selectively combine the thallium(III) anions and the dimeric cations. Thermolysis of the complex is accompanied by gold recovery and release of TlCl.

In the process of N,N'-bis(5-bromosalicylidene)-1,3-propylenediamine sorption by a perfluorosulfonic membrane donor-acceptor interaction of azomethine with membrane sulfo groups appears as considerable simultaneous shifts of absorption and fluorescence spectra compared to analogous azomethine spectra in alcohol solutions. An analysis of the observed changes suggests that the π*_N=C antibonding states of the azomethine molecule fragment are emitting.

An efficient synthesis of 6-(2-chloro-4-fluorophenyl)-9-phenylimidazo[1,2-a][1,8]naphthyridine derivatives by the reaction of phenacyl bromide with substituted heterocyclic amines in the presence of DABCO catalyst is described. Solid state conditions of the process accelerate accumulation of the targeted products with high yields and exclude formation of side-products. Antibacterial and fungal activities tests of all newly synthesized products demonstrate their pronounced potency, which is the highest for compounds 5c–5e. Molecular docking studies support well with the antimicrobial activity data accumulated for the products.

Five new substituted benzamide derivatives as ionic solids are prepared and characterized by FT-IR, ¹H, and ¹³C NMR spectroscopy. The crystal structure for compound 2 is determined by X-ray crystallography. The compounds are bio-assayed for their bactericidal, fungicidal, anti-oxidant, and urease inhibition activities. The molecular docking results accumulated for the compounds correlate with their biological activity and reveal high binding affinity towards jack bean urease.

The new complexes of 2-[(2-oxo-1,2-dihydroindol-3-ylidene)amino]butanoic acid, LH (where L = C₁₂H₁₁N₂O₃), with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) of general formulae MLCl·nH₂O, for Co(II), Ni(II) and Cu(II), and ML₂·H₂O for Mn(II) and Zn(II), where n = 1, 2 depending on M(II) ions, are synthesized. The complexes crystallize in a monoclinic system, and upon heating in the air (293–1173 K) decompose in three steps forming eventually the corresponding oxides of the metals(II). In the course of this process the organic ligand decomposes releasing the molecules of H₂O, CO₂, NH₃, CO, hydrocarbons, and additionally HCl for Co(II), Ni(II) and Cu(II) complexes. Magnetic moments of compounds are determined in the ranges of 76–303 and 2–300 K. All analyzed compounds, except that of Zn(II), demonstrate the paramagnetic properties with the ferro- and antiferromagnetic interactions between molecular centres.

The reaction of furfural with secondary amines and isopropyl cyanoacetate gave previously unkown diisopropyl esters of 8-(dialkylamino)-6-oxo-3-(2-furyl)-2,4-dicyanobicyclo- [3.2.1]octane-2,4-dicarboxylic acid.

Reaction of 2-chloro-N-(2,2-dichloro-1-cyanovinyl)acetamide with dimethylamine gave 5-(dimethylamino)-2-[(dimethylamino)methyl]-1,3-oxazole-4-carbonitrile, where aliphatic dimethylamino group was regioselectively alkylated with iodomethane. The resulting trimethylammonium salt reacted diastereoselectively with aromatic aldehydes to form new substituted 2-(oxiran-2-yl)-1,3-oxazoles.

The reaction between pyrocatechol and N,N,N',N'-tetraethylphenylphosphonous diamide was studied. It was found that the main reaction products are bisphosphorylated pyrocatehol and and the product of intramolecular cyclization, ester of pyrocatechol and phenylphosphonic acid.